#include"ST.h"
void StackInit(Stack* ps)
{
    assert(ps);
    ps->a = NULL;
    ps->top = 0;
    ps->capacity = 0;
}
void StackPush(Stack* ps, STDataType data)
{
    assert(ps);
    if (ps->top == ps->capacity)
    {
        int newcapacity = ps->capacity == 0?4 :(ps->capacity * 2);
        STDataType* newStack = (STDataType*)realloc(ps->a, sizeof(STDataType) * newcapacity);
        if (newStack == NULL)
        {
            perror("realloc fail");
            exit(-1);
        }
        ps->a = newStack;
        ps->capacity = newcapacity;
    }
    ps->a[ps->top] = data;
    ps->top++;
}
void StackPop(Stack* ps)
{
    assert(ps);
    assert(ps->top > 0);
    ps->top--;
}
STDataType StackTop(Stack* ps)
{
    assert(ps);
    assert(ps->top > 0);
    return ps->a[ps->top-1];
}
int StackSize(Stack* ps)
{
    assert(ps);
    return ps->top;
}
bool StackEmpty(Stack* ps)
{
    assert(ps);
    return ps->top== 0;
}
void StackDestroy(Stack* ps)
{
    assert(ps);
    free(ps->a);
    ps->a = NULL;
    ps->top = 0;
    ps->capacity = 0;
}